unique.data.table inconsistent with unique.data.frame when handling Inf

[ampu3ro]

I'm not sure if this is intentional but doesn't seem like it should be. Looks like forderv is probably the culprit.

library(data.table)

x <- c(0, Inf)
unique(data.frame(x))
#>     x
#> 1   0
#> 2 Inf
unique(data.table(x))
#>    x
#> 1: 0
unique(data.table(c(x, 1)))
#>     V1
#> 1:   0
#> 2: Inf
#> 3:   1

devtools::session_info()
#> - Session info ----------------------------------------------------------
#>  setting  value                       
#>  version  R version 3.5.2 (2018-12-20)
#>  os       Windows 7 x64 SP 1          
#>  system   x86_64, mingw32             
#>  ui       RTerm                       
#>  language (EN)                        
#>  collate  English_United States.1252  
#>  ctype    English_United States.1252  
#>  tz       America/New_York            
#>  date     2019-02-07                  
#> 
#> - Packages --------------------------------------------------------------
#>  package     * version    date       lib
#>  assertthat    0.2.0      2017-04-11 [1]
#>  backports     1.1.3      2018-12-14 [1]
#>  callr         3.1.1      2018-12-21 [1]
#>  cli           1.0.1      2018-09-25 [1]
#>  crayon        1.3.4      2017-09-16 [1]
#>  data.table  * 1.12.1     2019-02-07 [1]
#>  desc          1.2.0      2018-05-01 [1]
#>  devtools      2.0.1      2018-10-26 [1]
#>  digest        0.6.18     2018-10-10 [1]
#>  evaluate      0.12       2018-10-09 [1]
#>  fs            1.2.6      2018-08-23 [1]
#>  glue          1.3.0      2018-07-17 [1]
#>  highr         0.7        2018-06-09 [1]
#>  htmltools     0.3.6      2017-04-28 [1]
#>  knitr         1.21       2018-12-10 [1]
#>  magrittr      1.5        2014-11-22 [1]
#>  memoise       1.1.0      2017-04-21 [1]
#>  pkgbuild      1.0.2.9000 2019-02-07 [1]
#>  pkgload       1.0.2      2018-10-29 [1]
#>  prettyunits   1.0.2      2015-07-13 [1]
#>  processx      3.2.1      2018-12-05 [1]
#>  ps            1.3.0      2018-12-21 [1]
#>  R6            2.3.0      2018-10-04 [1]
#>  Rcpp          1.0.0      2018-11-07 [1]
#>  remotes       2.0.2      2018-10-30 [1]
#>  rlang         0.3.1      2019-01-08 [1]
#>  rmarkdown     1.11       2018-12-08 [1]
#>  rprojroot     1.3-2      2018-01-03 [1]
#>  sessioninfo   1.1.1      2018-11-05 [1]
#>  stringi       1.2.4      2018-07-20 [1]
#>  stringr       1.3.1      2018-05-10 [1]
#>  testthat      2.0.1      2018-10-13 [1]
#>  usethis       1.4.0      2018-08-14 [1]
#>  withr         2.1.2      2018-03-15 [1]
#>  xfun          0.4        2018-10-23 [1]
#>  yaml          2.2.0      2018-07-25 [1]
#>  source                                
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  Github (Rdatatable/data.table@4cf5f45)
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  Github (r-lib/pkgbuild@6e4ebdf)       
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#>  CRAN (R 3.5.2)                        
#> 
#> [1] C:/Program Files/R/R-3.5.2/library
```R

[arunsrinivasan]

Seems to be due to the change in logic of unique.data.table to implement things directly in this commit: 1fd3862#diff-a17242becd5cd79fa6fc4e916d0d6208

Taking a look now.

[arunsrinivasan]

This seems to be an issue with the new forderv implementation. See #3381. Have filed it as a HIGH priority. When fixed, this should automatically be taken care of as well.